Sporadic DMR activity.

[Lscott]

I scan the GMRS/FRS channels while sitting at my desk at work using a cheap radio. Sporadically I catch some DMR activity. It might persist for a day or so then it’s gone. I verified it was DMR by using my D878 I brought in and setup for promiscuous mode. Nothing was said that one could infer who or where the transmissions were originating from at the time.
 

Has anybody else noticed DMR, or other digital voice modes, on GMRS/FRS? As the service becomes more popular the temptation to run digital voice increases as the price for “cheap” or used digital radios comes down. 
 

Perhaps it’s time to put the squeeze on the FCC to authorize some form of digital voice before it gets out of hand like they did with the former GMRS/FRS combo radio mess.

Something like DMR, or NXDN, maybe both, are allowed. DMR would likely be the favorite while NXDN might be the lower cost solution. Note in Europe dPMR is very popular, similar to NXDN, and is used for their license free radio service.

https://en.wikipedia.org/wiki/Digital_private_mobile_radio

[WRQC290]

No objection to digital modes but, I doubt they would consider that proposal actionable for at least a decade out. They aren't exactly known for efficiency after all. I get the feeling they have an agenda they're already following, and it seems to focus on commercial services. Personal, 2 way, and hobby radio are an after thought for the time being.

[Lscott]

44 minutes ago, WRQC290 said:

No objection to digital modes but, I doubt they would consider that proposal actionable for at least a decade out. They aren't exactly known for efficiency after all. I get the feeling they have an agenda they're already following, and it seems to focus on commercial services. Personal, 2 way, and hobby radio are an after thought for the time being.

That would be disappointing. I think it’s going to happen with or without the FCC’s official blessing. They already look the other way with people using Part 90 radios on GMRS. Of course they can just ignore it like they did with 11M for decades then finally figured out the rest of the world moved on and allowed FM.

I have several commercial radios that are Part 95 certified and digital capable. Would be nice to use their full set of features on something other than the Ham bands.

[WRKC935]

there was a repeater on DMR on either 625 or 575 a while back here in central Ohio.  It seemed to have disappeared now.  But yes I have seen it happening too.

 

[gortex2]

If you listen long enough you will hear digital on GMRS and have over the years. I have listened to P25 as well as DMR (MotoTRBO) for almost 10 years. Back in NY there was a school that put in a DMR repeater on 575. After about a year of complaints about coverage they switched radio shops and then got a real license. To be honest I dont want the FCC to add any designators. There are many services that can use digital out there if one wishes to use digital.  

[tweiss3]

We had one DMR Repeater in the area that someone unlicensed put up. I gave them names, FRNs and addresses (they were hams using their ham DMR ids) and the FCC said thanks but we aren't going to touch it. I ended up talking about it with a few local hams, they knew which tower it was on, and the tower owner pulled the plug.

 

I'd like digital to be approved, the coverage distance improvement is huge, but who knows.

[Blaise]

Here in the NYS Capital District, we have at least one station using digital on channel 17(.600).  It renders the channel unusable for an hour at a time sometimes, and pops up several days a week.  It's quite frustrating.

[hfd376]

I had heard of a DMR repeater or repeaters being licensed as experimental on GMRS years ago. The FCC addressed digital modes for Part 95 A about the same time frame as using Part 90 radios. Their thoughts at the time were that the existing radios allowed were meeting the needs of the general public. I also feel that digital modulation would benefit the public, although the 900 MHz FHSS radios would fill this purpose. It would be nice to be able to have repeaters capable of digital available for GMRS.   

[WRCZ387]

3 hours ago, hfd376 said:

I had heard of a DMR repeater or repeaters being licensed as experimental on GMRS years ago.

I read a post over on radioreference awhile back, that there is a legit experimental licence for digital on GMRS, it's in Alameda, CA

https://apps.fcc.gov/els/GetAtt.html?id=234790&x=

[BoxCar]

1 hour ago, WRCZ387 said:

I read a post over on radioreference awhile back, that there is a legit experimental licence for digital on GMRS, it's in Alameda, CA

https://apps.fcc.gov/els/GetAtt.html?id=234790&x=

The experimental license expired last year (Aug 2021).

[WRCZ387]

1 hour ago, BoxCar said:

The experimental license expired last year (Aug 2021).

I just looked, they renewed it to August 1st, 2023

https://apps.fcc.gov/oetcf/els/reports/405_Print.cfm?mode=current&application_seq=107450 

[PACNWComms]

I took scan and monitor DMR and GMRS radios in my area, using legacy scanners for GMRS and an Anytone in promiscuous mode for DMR. In my area, UHF radio is so over saturated, it is also very common to hear digital modes in use. Then, there are the Garmin Rino radios that have been issued to search and rescue personnel, some National Guard (Army and Air) members, as well as Community Emergency Response Teams that pushed for FRS/GMRS use as the technology became cheaper. This, along with several radio shops that push new product very well, means there are many first generation XPR series Motorola Trbo radios proliferating the secondary market. 

As for digital use on GMRS frequencies, one of my first "catches" as a frequency and spectrum manager in the military was a unit that was using data and encryption on their military STX3000 UHF radios, programmed on GMRS frequencies. They said they did not have training frequencies that they could use. Checking the NTIA listings, they really did have official frequencies they could have used to stay legal, and after setting them straight, did not hear digital modes on GMRS, until after the FCC changes made in 2017. 

When the Motorola DTR series 900 MHz ISM band frequency hopping radios came out, they were sold as a great alternative to the saturated UHF radio market and users. This means I also hear many of them, being used in their defaulted state, on the included TalkGroups. 

 

[Lscott]

I think we’re going to hear more digital voice activity. There are plenty of choices for radios to use from the cheap Chinese models and the older but very useable commercial types all with digital voice features People are buying them and programming them up for GMRS and digital, either out of ignorance or just plain don’t give a sh*t attitude because I’m not going to get caught.

My feeling is the FCC will ignore it as long as possible until it reaches the point where the chaos on the band seriously degrades the usability. At that point they will have to make a tuff choice, either officially allow it with specific rules on where it can be used or get serious about enforcement. That’s what the FCC did with the rule changes back in 2017/2018 with the FRS/GMRS combo radios. The FCC gave up, though in the towel and just made the wide spread practice legal.

[gman1971]

Yep, hear plenty of DMR/P25 and other unknown modulations on GMRS/FRS, and MURS too.

@Lscott, agreed. However, I don't think its just the "don't give a sh*t about" attitude, really. I think its a matter of digital being better overall, and that it can withstand interference way better too. If you try side by side an XPR radio in digital vs FM modulation it becomes apparent that while FM sounds better when the other radio is close, once the other radio goes beyond a certain distance, or its in difficult terrain, or in RF congested areas, etc, the audio coming from the XPR in digital its pretty much crystal clear until the signal is completely gone.

G.

[Lscott]

4 hours ago, gman1971 said:

Yep, hear plenty of DMR/P25 and other unknown modulations on GMRS/FRS, and MURS too.

@Lscott, agreed. However, I don't think its just the "don't give a sh*t about" attitude, really. I think its a matter of digital being better overall, and that it can withstand interference way better too. If you try side by side an XPR radio in digital vs FM modulation it becomes apparent that while FM sounds better when the other radio is close, once the other radio goes beyond a certain distance, or its in difficult terrain, or in RF congested areas, etc, the audio coming from the XPR in digital its pretty much crystal clear until the signal is completely gone.

G.

Yeah, DMR does sounds good, but a bit funky. My issue is with those who know better but run digital voice anyway simply because they can and screw the rules. They set a bad example for everyone. Most people honestly want to follow the rules. The few who have the “don’t give a sh*t” mindset, believing the FCC will never enforce the rules, harbor a very narcissistic view where their wants are more important and don’t care who else has to put up with the mess their actions cause. That’s what ruined 11M through the 70’s and 80’s, linear amplifiers, free-banding etc. as an example. Now some of those idiots have discovered GMRS.

[gman1971]

1 hour ago, Lscott said:

Yeah, DMR does sounds good, but a bit funky. My issue is with those who know better but run digital voice anyway simply because they can and screw the rules. They set a bad example for everyone. Most people honestly want to follow the rules. The few who have the “don’t give a sh*t” mindset, believing the FCC will never enforce the rules, harbor a very narcissistic view where their wants are more important and don’t care who else has to put up with the mess their actions cause. That’s what ruined 11M through the 70’s and 80’s, linear amplifiers, free-banding etc. as an example. Now some of those idiots have discovered GMRS.

Well, at the end of the day its just a low bit-rate voice codec, so its never going to sound as good as analog signal in a high SNR scenario. The strong point for digital is error correction, which usually can translate into increased useful range... although a case for WFM can be made as well, or SSB... but that requires a lot of ear training to pick the nuances of weak signals... etc.

That is part of the reason why digital would be appealing to implement, so you can avoid getting hammered by interference, regardless of the source. I think the biggest issue doesn't come from "freebanders" these days, like it did in the 70s/80s. It now comes from a new enemy: the myriad of cheap electronics that spew RFI like its going out of style... the reason why the VHF band noise floor is high (and range is low) is not b/c some freebander dude running 1kW DMR while ragchewing, or a couple of CCRs pumping 50W, etc (I know, letting some of that vitriol out here... LOL), or someone running a 2kW VHF pirate station, etc, its b/c every darn LED fixture nearby pollutes the RF spectrum a tiny bit, then things like traffic light intersections emit RF noise through the roof, or every solar panel installation pollutes the RF spectrum 10-20 dB at a time as well...  So, when you add all that noise to your TX signal then you get a super-duper salad of IM (intermodulation) which further screws everything up. And the issue is only getting worse for all bands, too, including the UHF band as well. Soon the noise floor with be so high that you might not be able to use a radio at all. That is one of the reason why a lot of users have migrated from VHF to 900Mhz, to move away from the substantial increase in noise floor. Now, you can still make it work, but you need very high quality equipment, lots of filtering and potentially some sort of active noise phasing to get around the noise floor issue. Its just a matter of $$$$.

At this point, like I've discussed with some people, there is no way to put the genie back in the bottle, not unless the FCC starts strictly enforcing all aspects of RF, which starts by strictly enforcing cheap electronics RFI levels, things like LED fixtures and the like, which pollute the RF spectrum like crazy.

Ideally, GMRS should've been implemented like the DTR radios in the 900mhz spectrum, as a frequency hopping service so there would've been a lot more "room" in the limited UHF spectrum. But then again, even a FHSS scheme would've caused issues for the FM purists... 

In the end, there is no way to please everybody, somewhere, somehow, someone will not agree with what they see, and will be very vocal about it. 

G.

[Lscott]

9 hours ago, gman1971 said:

Well, at the end of the day its just a low bit-rate voice codec, so its never going to sound as good as analog signal in a high SNR scenario. The strong point for digital is error correction, which usually can translate into increased useful range... although a case for WFM can be made as well, or SSB... but that requires a lot of ear training to pick the nuances of weak signals... etc.

That is part of the reason why digital would be appealing to implement, so you can avoid getting hammered by interference, regardless of the source. I think the biggest issue doesn't come from "freebanders" these days, like it did in the 70s/80s. It now comes from a new enemy: the myriad of cheap electronics that spew RFI like its going out of style... the reason why the VHF band noise floor is high (and range is low) is not b/c some freebander dude running 1kW DMR while ragchewing, or a couple of CCRs pumping 50W, etc (I know, letting some of that vitriol out here... LOL), or someone running a 2kW VHF pirate station, etc, its b/c every darn LED fixture nearby pollutes the RF spectrum a tiny bit, then things like traffic light intersections emit RF noise through the roof, or every solar panel installation pollutes the RF spectrum 10-20 dB at a time as well...  So, when you add all that noise to your TX signal then you get a super-duper salad of IM (intermodulation) which further screws everything up. And the issue is only getting worse for all bands, too, including the UHF band as well. Soon the noise floor with be so high that you might not be able to use a radio at all. That is one of the reason why a lot of users have migrated from VHF to 900Mhz, to move away from the substantial increase in noise floor. Now, you can still make it work, but you need very high quality equipment, lots of filtering and potentially some sort of active noise phasing to get around the noise floor issue. Its just a matter of $$$$.

At this point, like I've discussed with some people, there is no way to put the genie back in the bottle, not unless the FCC starts strictly enforcing all aspects of RF, which starts by strictly enforcing cheap electronics RFI levels, things like LED fixtures and the like, which pollute the RF spectrum like crazy.

Ideally, GMRS should've been implemented like the DTR radios in the 900mhz spectrum, as a frequency hopping service so there would've been a lot more "room" in the limited UHF spectrum. But then again, even a FHSS scheme would've caused issues for the FM purists... 

In the end, there is no way to please everybody, somewhere, somehow, someone will not agree with what they see, and will be very vocal about it. 

G.

I pretty much agree with your points. Sooner or later digital voice will happen. I would much rather have the FCC get ahead of the game and institute some regulations to keep order rather than let things go and end up with the wild west of various modes trashing each other.

[gman1971]

4 hours ago, Lscott said:

I pretty much agree with your points. Sooner or later digital voice will happen. I would much rather have the FCC get ahead of the game and institute some regulations to keep order rather than let things go and end up with the wild west of various modes trashing each other.

Can't add more reactions today... so can't like your post... LOL. 

Yep, ideally... but it would seem the FCC is so far down the tubes, that it will take a rocket just to get to the basement... 

Digital modes seem to play quite well with each other, I must say. Specially DMR with other digital modes, since its TDMA so its not a continuous RF signal, so for P25 it will be a small hit in the BER... but for FM analogue, its probably the worst offender since it really sounds like a machine gun on full auto... 

G.

[Lscott]

2 hours ago, gman1971 said:

Can't add more reactions today... so can't like your post... LOL. 

Yep, ideally... but it would seem the FCC is so far down the tubes, that it will take a rocket just to get to the basement... 

Digital modes seem to play quite well with each other, I must say. Specially DMR with other digital modes, since its TDMA so its not a continuous RF signal, so for P25 it will be a small hit in the BER... but for FM analogue, its probably the worst offender since it really sounds like a machine gun on full auto... 

G.

I've read some comments where DMR seems to screw with analog CTCSS when it falsely will open the squelch at times when you really don't want to hear the digital noise.

[gman1971]

20 hours ago, Lscott said:

I've read some comments where DMR seems to screw with analog CTCSS when it falsely will open the squelch at times when you really don't want to hear the digital noise.

Yep, that happened to me plenty of times... You need DCS to get around that, at least it did in my situation.

G.

[Lscott]

1 hour ago, gman1971 said:

Yep, that happened to me plenty of times... You need DCS to get around that, at least it did in my situation.

G.

That doesn't help in my case. I'm monitoring the local mall security frequency about a 1/2 mile away from my office on analog FM . There is a hospital on the same frequency using DMR some miles away. I used the mall's repeater tone to block the DMR station, but it doesn't work consistently and the squelch will open at times.

[gman1971]

9 hours ago, Lscott said:

That doesn't help in my case. I'm monitoring the local mall security frequency about a 1/2 mile away from my office on analog FM . There is a hospital on the same frequency using DMR some miles away. I used the mall's repeater tone to block the DMR station, but it doesn't work consistently and the squelch will open at times.

That sucks. I know DCS fixed random squelch opening back in the day with my TM-V71a... 

G.

[JLeikhim]

Proper Wideband FM sounds much better than the IMBE and AMBE vocoders. I really dont see the advantage for GMRS.

Sent from my SM-T350 using Tapatalk

[Lscott]

4 hours ago, JLeikhim said:

Proper Wideband FM sounds much better than the IMBE and AMBE vocoders. I really dont see the advantage for GMRS.

Sent from my SM-T350 using Tapatalk
 

Except towards the  fringe of the coverage area. That's the attraction, better audio when the simple FM signal starts going into the crapper.

[tweiss3]

1 hour ago, Lscott said:

Except towards the  fringe of the coverage area. That's the attraction, better audio when the simple FM signal starts going into the crapper.

Exactly, and with a high profile site, can provide 17+ additional miles of usable range (that goes for any digital FM mode).